Metal–organic frameworks of general composition [M6(OH)4(O)4(PDC)6−x(Cl)2x(H2O)2x] with M = Zr, Ce, Hf; PDC2− = 2,5-pyridinedicarboxylate and 0 ≤ x ≤ 2 were obtained under reflux using formic, nitric or acetic acid as an additive. Rietveld refinements carried out using a fixed occupancy of the linker molecules according to the results of thermogravimetric measurements confirmed that the MOFs crystallize in the UiO-66 type structure and demonstrate that the structural models describe the data well. Further characterization was carried out by NMR spectroscopy, thermogravimetric analysis, Zr K-edge EXAFS- and Ce L3-edge XANES measurements. To highlight the influence of the additional nitrogen atom of the pyridine ring, luminescence and vapour sorption measurements were carried out. The hydrophilisation of the MOFs was shown by the adsorption of water at lower p/p0 (<0.2) values compared to the corresponding BDC-MOFs (0.3). For water and methanol stability cycling adsorption experiments were carried out to evaluate the MOFs as potential adsorbents in heat transformation applications.
Synthesis of M-UiO-66 (M = Zr, Ce or Hf) employing 2,5-pyridinedicarboxylic acid as a linker: defect chemistry, framework hydrophilisation and sorption properties
Lomachenko, K A;Lamberti, C;
2018-01-01
Abstract
Metal–organic frameworks of general composition [M6(OH)4(O)4(PDC)6−x(Cl)2x(H2O)2x] with M = Zr, Ce, Hf; PDC2− = 2,5-pyridinedicarboxylate and 0 ≤ x ≤ 2 were obtained under reflux using formic, nitric or acetic acid as an additive. Rietveld refinements carried out using a fixed occupancy of the linker molecules according to the results of thermogravimetric measurements confirmed that the MOFs crystallize in the UiO-66 type structure and demonstrate that the structural models describe the data well. Further characterization was carried out by NMR spectroscopy, thermogravimetric analysis, Zr K-edge EXAFS- and Ce L3-edge XANES measurements. To highlight the influence of the additional nitrogen atom of the pyridine ring, luminescence and vapour sorption measurements were carried out. The hydrophilisation of the MOFs was shown by the adsorption of water at lower p/p0 (<0.2) values compared to the corresponding BDC-MOFs (0.3). For water and methanol stability cycling adsorption experiments were carried out to evaluate the MOFs as potential adsorbents in heat transformation applications.File | Dimensione | Formato | |
---|---|---|---|
OpenAccess_version.pdf
Open Access dal 29/11/2018
Descrizione: Open access version
Tipo di file:
POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione
932.46 kB
Formato
Adobe PDF
|
932.46 kB | Adobe PDF | Visualizza/Apri |
18__UiO_66_CeZrHf.pdf
Accesso riservato
Descrizione: Published article
Tipo di file:
PDF EDITORIALE
Dimensione
3.37 MB
Formato
Adobe PDF
|
3.37 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.